DOA Estimation of Coherent Signals on Coprime Arrays Exploiting Fourth-Order Cumulants

TL;DR

This paper introduces a novel method for estimating the directions of coherent signals using coprime arrays and fourth-order cumulants, enhancing accuracy by exploiting array structure and supplementary sensors.

Contribution

It proposes a new fourth-order cumulant matrix and a generalized spatial smoothing scheme tailored for coprime arrays to improve DOA estimation of coherent signals.

Findings

Effective resolution of coherent signals demonstrated in simulations

False peak suppression achieved with supplementary sparse array

Method outperforms traditional techniques in accuracy and robustness

Abstract

This paper considers the problem of direction-of-arrival (DOA) estimation of coherent signals on passive coprime arrays, where we resort to the fourth-order cumulants of the received signal to explore more information. A fourth-order cumulant matrix (FCM) is introduced for the coprime arrays. The special structure of the FCM is combined with the array configuration to resolve the coherent signals. Since each sparse array of the coprime arrays is uniform, a series of overlapping identical subarrays can be extracted. Using this property, we propose a generalized spatial smoothing scheme applied to the FCM. From the smoothed FCM, the DOAs of both the coherent and independent signals can be successfully estimated on the pseudo-spectrum generated by the fourth-order MUSIC algorithm. To overcome the problem of occasional false peak appearing on the pseudo-spectrum, we use a supplementary sparse array whose inter-sensor spacing is coprime to that of either existing sparse array. From the combined spectrum aided by the supplementary sensors, the false peaks are removed while the true peaks remain. The effectiveness of the proposed methods is demonstrated by simulation examples.